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java - 如何在android中为自定义视图创建setter和getter

问题描述

我正在构建一个扩展视图并为图像获取参数的自定义视图。到目前为止，我一直在实现从可绘制对象和服务器（通过字符串 URL）绘制图像。

class CustomView(context: Context, attrSet: AttributeSet) : View(context){

    private var typedArray = context.obtainStyledAttributes(attrSet, R.styleable.CustomView)
    private var viewColor = typedArray.getColor(R.styleable.CustomView_viewColor, Color.WHITE)
    private var viewSize = typedArray.getDimensionPixelSize(R.styleable.CustomView_viewSize, 200)
    private var rect = Rect(50, 50, this.left+viewSize, this.top+viewSize)
    var viewImage = typedArray.getResourceId(R.styleable.CustomView_viewImage, -1)
    var imageBitmap:Bitmap?=null
    var imageString = typedArray.getString(R.styleable.CustomView_imageString)


    val radius = 100f
    var cx = 0f
    var cy = 0f
    private var paint = Paint(Paint.ANTI_ALIAS_FLAG)
    private var circlePaint = Paint(Paint.ANTI_ALIAS_FLAG)
    private var labelPaint = Paint(Paint.ANTI_ALIAS_FLAG)
    init {

        paint.color = viewColor
        circlePaint.color = Color.parseColor("#000000")
        labelPaint.color = Color.parseColor("#000000")
        typedArray.recycle()
        try {
            val iStream = URL(imageString)
            imageBitmap = BitmapFactory.decodeResource(resources, viewImage) ?: BitmapFactory.decodeStream(iStream.openStream())

        }catch (e:Exception){
            Log.i("Image", "Kindly provide a valid image")
        }
    }

    override fun onDraw(canvas: Canvas?) {

        if(cx == 0f || cy == 0f){
            cx = (width/2).toFloat()
            cy = (height/2).toFloat()
        }

        canvas?.drawRect(rect, paint)
        canvas?.drawCircle(cx, cy, radius, circlePaint)

        if (imageBitmap != null){
            canvas?.drawBitmap(imageBitmap!!, 50f, 100f, null)
        }
    }
}

我还希望能够在运行时在 xml 之外更改此值，例如在活动或片段中以使其动态化。

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val url =
            "https://dyl80ryjxr1ke.cloudfront.net/external_assets/hero_examples/hair_beach_v1785392215/original.jpeg"
        customView.imageString = url
    } 
}

标签： javaandroidandroid-studiokotlinview

解决方案

在 CustomView 类中，将 init 函数中的行设置为如下所示的设置函数：

class CustomView(context: Context, attrSet: AttributeSet) : View(context) {
    //setups

    init()
    {
        setupFunction(imageString)
    }

    fun setupFunction(url: String) {
        paint.color = viewColor
        circlePaint.color = Color.parseColor("#000000")
        labelPaint.color = Color.parseColor("#000000")
        typedArray.recycle()
        try {
            val iStream = URL(imageString)
            imageBitmap = BitmapFactory.decodeResource(resources, viewImage)
                ?: BitmapFactory.decodeStream(iStream.openStream())

        } catch (e: Exception) {
            Log.i("Image", "Kindly provide a valid image")
        }
    }
    onDraw()
}

现在 setupFunction() 可以在每次你想要这样的时候从你的 Fragment 或 Activity 调用：

customView.setupFunction(url)

并且视图将根据需要启动。

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